The Office began its cental filing system in June 1975. Incoming files, as well as materials already collected, were classified using a two-letter coding system to indicate the category to which the files were assigned. That classification system has been retained in this archival series as indicated in the arrangement section that follows.

The Office and its components collected data and information from a wide variety of sources from within city government and from outside agencies, governmental and private. Very little weeding was done when the records were originally processed during the mid-1980s, with the result that a considerable amount non-local data remains in the files. In some instances where the contents of a file had already been cataloged separately in the City Documents collection (or in other NOPL collections), the original file name has been preserved along with a "see" reference to the call number of the cataloged item.